It’s a good idea to require accounts to be validated before they can be used to create content. Somebody created an account with my email address and was able to sign in and create content. As a result, I was getting notification of comments and other automatic emails which I would consider to be spam, as I never solicited email from prezi.com.
Accidentally creating an account with a typo in one’s email address happens from time to time; that’s fine. But to prevent random people from getting lots of unsolicited mail, it’s good practice to require the new account holder to verify their account by clicking a link sent to their email address.
If this is not addressed, it leaves open the possibility of harrassing somebody by creating an account using their username, and then creating a presentation with embarrassing content.